Transformer and application of the same to heating



Deco 18 1923. 1,478,262

H. E. SNODGRASS ET AL TRANSFORMER AND APPLICATION OF THE SAME 'ro HEATING 4 Sheets-Sheet 1 Filed Feb. 18. 1921 ATTORNEYS INI ENTO S Dec. 18 1923.

H. E. SNODGRASS ET AL TRANSFORMER AND APPLICATION OF THE SAME T0 HEATING Filed Feb. 18, 1921 4 Sheets-Sheet 2 IN VEN 'I'ORS ATTORNEYS Dec. 18 1923.

H. E. SNODGRASS ET AL TRANSFORMER AND APPLICATION OF THE SAME T0 HEATING Filed Feb. 18. 1921 4 Sheets-Sheet 5 f INVENTORS W ATTORNEYS Dec. 18 1923. 1,478,262

H. E. SNODGRASS ET AL TRANSFORMER AND APPLICATION OF THE SAME To HEATING 4 Filed Feb. 18. 1921 4 Sheets-$heet 4 MWINVENTORS M Tr-@227 ATTORNEYS Patented Dec. 18, 1923.

UNITED: STATES 1,478,262 PATENT OFFICE.

HARLANII. SNODGRASS, 0F SU'IJIIMIT, AND THOMAS M. HUNTER, OF NEWARK, NEW JERSEY, ASSIGNORS, BY MESNE ASSIGNMENTS, TO NEWARK TUBE COMPANY, OF NEWARK, NEW JERSEY, A CORPORATION OF NEW JERSEY.

TRANSFORMER AND APPLICATION 0]? v THE SAME TO HEATING.

Application filed February 18, 1921. Serial No. 446,050.

To all whom it-mag concern:

Be it known that we, HARLAN E. SNOD' GRASS and THOMAS M. HUNTER. citizens of the United States, residing at Summit, in thecounty of Union and State of New Jersey, and Newark, in the county of Essex and State of New Jersey, respectively, have invented certain new and useful Improvements in Transformers and Application of the Same to Heating, of which the following is a specification.

Our invention more particularly relates to a novel form'of transformer and its application to welding and similar heating operations. Our present application is a continuation in part of our application Serial Number 399,449 which was filed in the Patent Office on or about July 28, 1920.

Our invention will best be understood by reference to the accompanying drawings, in which Figure 1 is a side elevation of a welding apparatusin which we have illustrated one embodiment of ourv invention; Fig. 2 is an end View, partially in section, of the device shown in Fig. 1; Fig. 3 is a longitudinal section through the transformer and associated parts; Fig. 4 is a cross section taken along the line 4-4 of Fig. 3; Fig. 5, is a side view of the laminated core for the transformer with the filling pieces for the opening omitted; Fig 6 is a plan view of the core shown in Fig 5; Fig. 7 is a detail view illustrating one of the filling pieces for' the opening of the core of the transformer; Fig. 8 is a detail view illustrating our invention applied to butt welding, Fig. 9 isa similar view illustrating our invention applied to lap welding, Fig. 10 isan end view, with the supporting member omitted, and Fig. 11 is a side view of a modified form of transformer "embodying our invention, and Fig. 12\ is an end view similar to Fig. 10, and Fig.{ 13 is aside view of a further modification.

Referring, now, to the drawings, 10 is the frame of a Welding machine provided with standards 10, 10*. An operating shaft 11, which when the device is to be air-cooled, is preferably provided with a central passage 12, has its bearing at 13 1n the standards 10*, 10". The shaft is preferably verti cally adjustable by screws 14 in a known manner, and is driven from any suitable source of power through suitable connections here shown as a sprocket-Wheel 15. The air-supply pipe 16, in' the form of our invention here illustrated, supplies air to the passage 12 in the hollow shaft 11. The end of the shaft 11 is preferably provided with a supporting member 17, Which-is provided with a central opening screwthreadcd at 18 to engage the screw-threaded end of the shaft 11, the supporting member abutting against a flange 19 formed on the shaft 11. The transformer, which is here shown as rotatable and which is preferably secured to the member 17, comprises a secondary 20, which may conveniently be formed of cast metal, and which in the form of-ou'r invention illustrated in Figs. 1 to 7, comprises a shell having a face plate 21 electrically connected to and preferably integral with one end of an axis 22 extending axially through the transformer, the central passage 22 communicating with the central passage 12 of the shaft 11. The secondary shell also comprises a cylindrical part 23, preferably integral with the face plate 21, and preferably formed with openings 24 for ventilating purposes. The opposite side of the secondary shell is closed by a plate 25 which may be screw-threaded on its periphery, as at 26, to engage a similar screw-threaded part on the inner side of the shell 23. The plate 25 is provided with a central opening 27, which is of a slightly reater diameter than the axis 22, so that the plate 25 is spaced from the axis 22 sufiicientlv to insulate the same therefrom. A core 28 for the transformer, preferably annular in fornnis located within and, in the form shownin Figs. 1 to 7, entirely enclosed by the shell of the secondary of the transformer, which constitutes a chambered body, the shell of the secondary of the transformer being electrically continuous in the direction of the generated current throughout the region of the corei. e., without the inner side of the core. The secondary completely enclosing the core and primary, as described, may be considered as made up of an indefinite number of conductors symmetrically arranged with reference to the axis thereof, thus providing for a magnetic, mechanical and electricalbalance under load conditions, and this balance is not affected by the rotation of the transformer. It will be apparent, for example, from an inspection of Fig. 3,

which may represent a section through the transformer taken along the axis at 1 any angle, that for each assumed conducting loop of the secondary around the core and primary, there will be a loop of equal length on the opposite side of the axis of the transformer and symmetrically arranged with reference to said axis. The core. maybe held in position within the secondary by bolts 29 extending'through the core and through the plates 21 and 25, respectively. The core v28 is covered by suitable insulation 30 and is surrounded bya primary winding 31,

preferably in the form of a flatribbon, and wound edgewise around the core. "When the winding is made in ribbon-form and is formed before the winding operation, it is necessary to provide an opening in the core which is closed after the winding'is placed in position. Referring particularly to Figs. 5, 6 and 7 it will be seen that the'core is provided at one side with an opening 32 formed by making the laminations 28v from which the core is formed somewhat less than a complete ring, the annualr laminated rings being completed by filler pieces 28, such as shown in Fig. 7. Adjacent laminated sheets or rings are preferably angularly displaced, as best shown in Fig. 6, so that one end of a given filler piece will lie between two alternate segments which project beyond the adjacent end of the intermediate segment. The secondary of the transformer is secured to the supporting member 17 by bolts or screws 33, suitable insulation being interposed between the; side 21 of the secondary and the supporting member 17, and

suitable insulating material also being inter-' posed. between the bolts 33 and the member 17, as clearly shown in Fig. 3. Current is supplied to t e primary of the transformer by collector rings 34, 34: se cured to the face plate 21 by bolts 35, suit; able insulation being interposed between the bolts and "the plate. Terminals 36 and 37 connect the primary terminals to the re spective collector rings. Alternating current is carried to the collector rings from by bolts 42. The two contact rolls 39 and.

40 are also formed on their inner edges with peripheral recesses, which together form a groove 43 adadpted to engage a tube which is to be welded; Whenthe device is used for welding, a second roll 44, also provided with .a peripheral groove, is disposed below the unitary roll and is mounted on a shaft 45 having its bearings at 46 in the brackets 10. The tube, which is illustrated at 47, passes through suitable guides 48 between the welding rolls 39, 40 and the lower roll 44, and over suitable-supporting rolls 419, it being understood that the seam of the tube to be welded registers with the insulation 41 between the contact members 39 and 4.0. The work may be cooled by air supplied by a pipe 50 passing through a nozzle 51.

In the operation of the welding machine illustrated, the relatively high voltage, low

current of the primary is changed to a low voltage, high current in the secondary, which terminates in the contact members 39 and 4:0, and when a tube is passed throu h the machine, the current passes from t e metal on one side of the seam to the metal on the other side of the seam, thereby welding the tube. The current is, of course carried to the work at one point on the periphery of the electrodes, which point advances around the periphery of the electrode as the device rotates. Since,'however,' the electrode 40 makes contact with the end plate 25 near the axis 22, and the electrode 39 makes annular cont-act with the axis 22, and since these two contacts are in closeproximity to each other and within the core 28, it will be apparent that the secondary is made up of an I infinite number of conducting loops which form complete turns around the magnetic core and rimary winding and which are magneticall closely associated therewith. It is, there ore, apparent that substantially uniform current density will be induced in each integral portion of theshell and axis, constituting the secondary and flow to the electrodes 39, 40 as equipotential points, said electrodes forming the poles of the secondary. In consequenceof the uniform current distribution in each integral portion of the shell and axis, and the close magnetic association of the secondary with the primary winding and core throughout the entire magnetic path, the leakage reactance of the two windings when considered together and the .leakage inductance of each winding separately are reduced to a minimum. The total 'reactance and impedance of the transformer will, therefore, below and the power factor high, and in practice we have obtained a power factor as high as ninety-five per cent,

and even higher, under unusually heavy current loads at: extremely low voltages. The device is, therefore, highly eflicient and has been found satisfactory in practice.

Furthermore, the potential is substantially uniform on each of the electrodes 39 and 40, and the current density is substantially uniform in each integral portion of the shell and axis, and this uniformity is not dependent upon the diameter of the electrodes, but upon the relation of their points of contact with the end plate and axis 22,

ectively.

ring the operation of the machine, air is preferably passed from the pipe 16 through the shaft 11 and. the passage 22 of res " the axis 22, in order to cool the transformer and the cont-act members. Additional means are also preferably provided for cooling the machine, comprising an air-supply pipe,

plied to lap welding, in which case one of the contact members 40 is made of a less diameter than the contact member 39" and engages one plate 52 while the other member 39 engages a second plate 53", which forms a lap joint with the plate 52 In Figs. 10 and 11 we have shown a modified formof our invention in which the secondary of the transformer comprises a plurality of U-shaped conductors 23 symmetrically arranged with reference to the axis of the transformer and which form with the axis conducting loops surround- 'ing the core and primary. It will be apparent that the advantages of themagnetic mechanical and electrical balance, under load conditions, will be present in this form of our invention. 1

In Figs. 12 and 13 we have illustrated a still further modification of our invention in which the core is rectangular in form, and the primary 31 is arranged in separate sections. The secondary here comprises separate conducting loops 23 as in the case of Figs. 10 and 11. IVhile in Figs. 10 to 13 we have illustrated four separate conduct-ing loops surrounding the core and primary, it will of course be understood that any desired number of conducting loops may be used, so long as the symmetrical arrangement thereof is preserved.

It will be apparent that the-device made in accordance with our invention is compact,

that it eliminates all sliding or moving contacts in the secondary circuit, and that the contact-members which project to one side of the transformer are readily accessible. It will further be apparent that both windings form a short path for their currents; that a uniform current density is induced in each integral portion of the secondary shell and axis; that the primary and secondary currents are closely associated with each other and with the core throughout the entire magnetic path, thereby reducing the resistance, reactance, stray field or eddy-current losses in the transformer as a whole, over other known forms of construction. The efliciency of the transformer will, therefore, be high, and in practice we have obtained an efliciency of ninety-seven per cent and even higher under commercial conditions.

While we have illustrated the referred embodiment. of our invention, it Wlll be un- -derstood that the transformer described may be used for operations other than welding, and that the machine embodying the transformer may be used for heating operations other than electrical welding.

What we claim and desire to secure by Letters Patent of the United States is:

1. A heavy current transformer for heating and the like, comprising a closed core, a primary surrounding said core, and a secondary comprising conductors .surrounding the core and symmetrically arranged with reference to the axis of said trans- ..former, and constructed and arranged to produce a substantially uniform distribution of current in said secondary.

2. A heavy current rotatable transformer for heating and the like, comprising a closed core, a primary surrounding said core, and a secondary surrounding said core and primary and comprising conductors symmetrically arranged around th e core with reference to the axis of said transformer, and constructed and arranged to produce a substantially uniform distribution of current in said secondary.

3. A transformer for heating and the like comprising a core, a primary surrounding said core, and a heavy current secondary completely enclosing said core and primary and electrically continuous around said core, and constructed and arranged to producea substantiallyuniform distribution of current in said secondary.

4. A transformer for heating and the like comprising a core, a primary surrounding said core, and a heavy current, secondary enclosing said core and primary and electrically continuous throughout the region of said core, and constructed and arranged to produce a substantially uniform distribution of current in said secondary.

5. A transformer for heating and the like comprising a continuous core, a primary surrounding said core, and a heavy current secondary enclosing said core and prlmary and electrically continuous throughoutthe region of said core, and constructed and arranged to produce a substantially uniform distribution of current in said secondary.

6. A transformer for heating and the like comprising an annular core, a primary surrounding said core, and a heavy current secondary enclosing said core and primary and electrically continuous throughout the region of said core, and constructed and arranged to produce a substantially uniform distribution of current in said secondary.

7. A transformer for heating and the like comprising an annular core, a primary surrounding said core, and a heavy current secondary comprising an axis extending through said core and a shell electrically continuous with said axis at one end thereof and completely enclosing said core and primary. (v

8. A. transformer'for heating and the like comprising an annular core, a primary surrounding said core, a heavy current secondary comprising an axis extending through said core and a shell electrically continuous with said axis at one end thereof and completely enclosing said core and primary, and electrodes for said secondary located at one side of said transformer and electrically connected to said axis and to arranged about the axis of said transformer and electrically continuous outside of the periphery of the core, and electrodes connected to .the ends of said loops.

11. In a heating device, a rotatable transformer comprising a core, a primary surrounding said core, and achambered secondaryenclosing said core and primary and electrically continuous through-out the region of said core. v a

12. In a heating device, a rotatable transformer comprising a core, a primary surrounding said core, a secondary comprising an axis extending through said core and having a plurality of looped conductors electrically connected at one end to said axis and symmetrically arranged about the same, and electrodes at the side of said transformer connected to said axis and to the free ends of said loops respectively.

13. In a heating device, a rotatable transformer comprising a core, a primary surrounding said core, a secondary comprising an axis extending through said core and a shell electrically continuous with said axis at one side and extending close to said axis at its other side, said shell enclosing said core and said primary, and electrodes at vof said transformer and rotating therewith:

15. In a heating device, a rotatable trans former comprising an annular core, a primary surrounding said core, a secondary comprising an axis extending through said core and a shell electrically connected at one side to said axis and at the other side extending adjacent thereto but insulated therefrom, and electrodes mounted on said axis and electrically connected to said axis and to one side of said shell respectively.

16. In a heating device, a rotatable transformer comprising an annular core, a primary surrounding said core, a secondary comprising an axis extending through said core and a shell electrically connected at one side to said axis and at the other side extending adjacent thereto but "insulated therefrom, and a unitary contact roll mounted on said'axis and comprising two insulated contact members electrically connccted to said axis and to the free side of said shell respectively.

.17. In a heating device, a transformer comprising a core, a primary surrounding said core and a secondary comprising an axis extending through said core and a shell electrically connected to said axis at one end thereof, and electrodes located at one side of said transformer and forming annular electrical connections with said axis and said shell respectively.

18. In a heating device, a rotatable transformer comprising a core, a primary surrounding said core and a secondary comprising an. axis extending through said core and a shell-electrically connected to said axis at one end thereof, and contact rolls located at one side of said transformer and rotating therewith and forming annular electrical connections with said axis and said shell respectively.

19. A heating device comprising a trans-- former having a chambered metallic body forming its secondary and an axis through said body electrically connected to one end of said body and passing near to the opposite end but insulated therefrom, and electrodes each-of which is of substantially equal potential throughout connected to the free end of chambered body and axis respectively.

20. In a heating device, a transformer comprising a continuous core and a primary Winding surrounding said core, a metallic envelope enclosing'said core and said primary and constituting the secondary of the transformer, an axis extending through said envelo and electrically connected to one side 0 said envelope and insulated from the other side thereof, and electrodes each of which is of. substantially equal potential throughout forming continuous contact with the free side of said envelope and with the free end of said axis, respectively.

21. A transformer comprising a core, a primary and a secondary consisting of a chambered body with a part protruding axially through the center of-said body, said secondary completely enclosing the primary and the core, and electrodes each of which is of substantially equal potential throughout forming continuous contact with the free ends of the chambered body and the axially protruding part, respectively.

22.In a tube welding apparatus, in combination, a rotatable transformer, a twopart welding wheel side byside therewith, the secondary of said transformer being connected to the respective parts of said welding wheel.

23. In a tube welding apparatus, in combinatipn, a rotatable transformer, a twopart welding wheel in axial ali nment with said transformer and indepen ent thereof,

- former,

the secondary of said transformer being connected to the respective parts of said welding wheel.

24. In a tube welding apparatus, in combination, a rotatable transformer, a twopart welding wheel of lesser diameter than and in axial ali nment with said transthe secom lar of said transformer being connected to the said welding wheel.

25. A transformer comprising an annular core, a primary, and a secondary formed of looped conductors surrounding the primary and core and symmetrically arranged about the axis of the transformer, the axis of the transformer lying substantially in the plane oftach loop.

26. In a welding apparatus, a rotatable transformer com rising an annular core, a primary, a secondary formed of looped conductors surrounding'the primary and core and symmetrically arranged about the axis of the transformer, the axis of the transformer lying substantiall in the plane of each loop, and weldin electrodes to which the respective ends 0 the loops are connected respective parts of HARLAN E. SN ODGRASS. THOMAS M. HUNTER. 

